The present invention relates to an improved weft presenting device for use in looms with selective weft feed, which weave with a stationary weft supply from which the thread is intermittently drawn into successive sheds.
In the field of weaving machines, devices are already known to carry out the presenting of weft threads to the members (usually grippers) for gripping and carrying the threads into the shed of weaving looms of the so-called type with weft feed. Such devices -- better known as presenting devices -- are substantially meant to arrange one at a time, for being gripped by the gripping member, the various weft threads -- usually of different characteristics and especially of different colours -- forming the fabric on the loom. For this purpose, the presenting devices generally comprise a plurality of presenting members formed by rods the tipped end of which is crossed, through an appropriate hole, by the thread to be presented. Usually, such rods are arranged parallel to one another, partially contained inside a case from which they come out, one at a time, to present their own weft thread close to the gripping and carrying member, under the control of an electromagnet, which is in turn energized by the selection devices which form the pattern of the fabric being woven in the loom. As a matter of fact, the known presenting devices carry out only a partial presenting of the selected weft thread, which they separate from the other threads, causing it to advance close to the gripping and carrying member; the presenting operation is then completed by a hook, which grips the thread carried by the rod projecting from the presenting device and appropriately deviates the path of said thread, to allow it to be grasped by the gripping and carrying member. In the known presenting devices, the return of the rods to a rest position is controlled by a return spring, with all the drawbacks deriving from a control of this type, said drawbacks becoming all the more serious -- with further negative effects on the regular running of the loom -- when trying to increase the loom working speed, as happens in the most modern of such weaving machines. p The object of the present invention is to provide an improved presenting device, suited for modern looms with a high number of beatings up per minute, eliminating, on one hand, the drawbacks deriving from the spring return of the presenting rods, and making it possible, on the other hand, to simplify the operation of presenting the weft, by avoiding the use of the hook.